Portable elevator tower



June 27, 1961 s. T. BUCK 2,990,034

PORTABLE ELEVATOR TOWER Original Filed March 20, 1956 ii 24o n 59%- 1: '244 zoe 206 207 zoo FIG. -7

IN VEN TOR. STEWRD T. BUGA BY fm@ ATTO United States Patent Oce 2,990,034 Patented June 27, 1961 2,990,034 PORTABLE ELEVATOR TOWER Steward T. Buck, 1450 Neeb Road, Cincinnati 38, Ohio Original application Mar. 20, 1956, Ser. No. 572,688, now Patent No. 2,850,191, dated Sept. 2, 1958. Divided and this application Jan. 31, 1958, Ser. No. 714,457

2 Claims. (Cl. 187-80) This invention relates to a portable hoisting tower assembly, and more particularly to a sectional hoisting tower having a platform elevator loperably associated therew1th.

The present application is a division of U.S. application Ser. No. 572,688 led March 20, 1956, now Patent No. 2,850,191 issued September 2, 1958. The present invention relates to an improved safety brake mechanism for use with the elevator of a portable hoisting tower. The portable hoisting7 tower is disclosed in the forernentioned parent application, and the tower is utilized in association with a transport vehicle, the weight of the tower when fully erected being sustained by a supporting surface through the lowermost section of the tower to thereby entirely relieve the transport vehicle. The structure associated with the automatic safety brake means of the present invention will be fully appreciated when considering the aforementioned parent application.

An object of the invention is to provide the elevator of a hoisting tower assembly with fully automatic elevator supporting safety means which are automatically rendered operable in the event the supporting cables should break or become slack.

FIGS. 1 and 2 are front views of the safety device comprising a detail of the present invention with parts thereof broken away and with the elevator and hoisting tower indicated in broken outline, for clarity of detail and understanding, showing the device in normal inoperative and operative positions, respectively.

FIGS. 3 and 4 are side views of FIGS. 1 and 2, respectively.

FIG. 5 is a top elevational view of a brake shoe comprising a detail of the invention.

FIG. 6 is a sectional View taken on line 6-6 of FIG. 5.

FIG. 7 is a side elevational view of the brake shoe of FIG. 5.

A conventional elevator supporting cable is indicated by reference numeral 80, and the vertical elevator-track or elevator-guide dening elements are indicated by the letter A. These portions are associated with the hoisting tower as more fully disclosed in the aforementioned parent application.

With reference now to FIGS. l through 4, the numerals 200 denote pressure plates rigidly secured by brackets 201 to the upstanding side members 202 of the elevator assembly 62, whereby they will be disposed in closely spaced parallelism or in actual light, sliding relationship with the forward face of the vertical elevator. track or elevator guide dening elements A.

The numerals 206 denote elongate brake shoes pivotally secured by parallel links 208 to side members 202 for movement between the normal, inoperative positions of FIGS. l and 3, in spaced relationship with the rear face of track or guide elements A, to the operative positions of FIGS. 2 and 4, in positive locking engagement with said elements.

The brake shoes are automatically shifted from inoperative to operative positions, should the elevator supporting cable 80 break or become slack.

With particular reference now to FIGS. 1 and 2, the numerals 210 denote vertical guide elements spanning horizontal plates 212 and 214 and upon which pulley cage 216 is slidably mounted. Plates 212 and 214 are rigidly secured to the elevator platfrom assembly.

A plate 218 is secured to and carried by the pulley cage for movement therewith, the ends of said member being provided with pivot pins 220. The outer end of each of a pair of arms 222 is pivotally mounted as at 224 to side members 202. The inner ends of arms 222 are provided with elongate slots 226 which slidably engage pins 20, thereby permitting the arms to be moved between the positions of FIGS. l and 2.

A tension spring 230 is disposed between plate 214 and the lower end of rod 232, the upper end of which is secured to lower plate 234 of the pulley cage, whereby the pulley cage will be normally and yieldably urged downwardly from the position of FIG. 1 to that of FIG. 2 by the action of spring 230.

The weight of the elevator when lifted by cable will oppose and overcome the counterforce of spring 230 for disposing the pulley cage and arms 222 in the relative positions illustrated in FIGS. 1 and 3, in which condition brake 206 and pressure plates 200 are disposed in inoperative position with respect to guides A, thereby permitting the elevator to be freely moved along the guides of the hoisting tower assembly.

However, if cable 80 should break or become slack, pulley cage 216 will be instantly lowered to the position of FIG. 2, thereby swinging the outer end 223 of arms 222 upwardly about and relative to pivots 224 for engaging and lifting the uppermost of the mounting ears 207 which are rigidly secured to the brake shoes 206 and which are pivotally connected to parallel links 208 at 209. In this manner the entire length of the brake shoes will be uniformly and positively jammed against the rear surface of guide elements A. The jamming action will be augmented by pressure plates 200 which, being disposed closely adjacent or in sliding contact with the opposite or forward face `of guide elements A, will, in elfect, result in the front and rear faces thereof being compressed between adjacent faces of the pressure plates and brake shoes, whereby relative motion between .the elevator and the hoisting tower will be positively precluded.

With particular reference now to FIGS. 3 and 4, the numerals 240 denote stop elements engageable by and which limit the upward swing of parallel links 208.

In FIGS. 5, 6 and 7 I have illustrated the preferred construction of the brake shoes which preferably include an arcuate braking surface 242 which is serrated as at 244 for providing a surface which will actually cut into the rear surface of guide elements A whenever the cable 80 is slack or broken and the parallel links 208 have been shifted to the horizontal position of FIG. 4.

In this manner I have thus provided simple, inexpensive, yet highly eicient, yfoolproof safety means in conjunction with the elevator of a hoisting tower.

What is claimed is:

l. An elevator tower comprising a pair of laterally spaced vertical tracks, a platform having a pair of side members secured to and extending upwardly from one end of said platform, said side members disposed in spaced parallelism with said tracks, means guiding said side members along said tracks with the said plat-form projecting outwardly from said side members, means including a cable for supporting and moving said platform relative to said tracks, an elongate pressure plate iixedly secured to and carried by each of said side members, said pressure plates disposed one each in parallel sliding relationship with a face of said tracks, an elongate brake shoe for each of said pressure plates, a pair of vertically spaced parallel links pivotally interconnecting a brake shoe to a side member for movement, in parallelism with a corresponding pressure plate, between lowered inoperative position spaced from a track and raised operative position in engagement with said track opposite the pressure plate, an actuator arm vfor each brake shoe, means pivotally securing said arms to said side members for disposing the tree outer end of an arm beneath and intermediate the length of one Yof the parallel-links of abrake shoe, each actuator arm being supported ffor pivotal movement about an axis which is substantially normal to the axis of pivotal movement of the parallel links connected to the associated brake shoe whereby the direction of movement of each actuator arm is substantially normal to the direction of movement of the associated brake shoe, means normally urging the outer ends of said arms upwardly for shifting and maintaining the brake Shoes in raised operative position against their respective tracks, and other means responsive to suspension of the elevator Vfrom said cable for shifting said arms to an inoperative position.

2. An elevator tower comprising a pair of laterally spaced vertical tracks, a platform having a pair of side members secured to and extending upwardly from one end of said platform, said side members disposed in spaced parallelism with said tracks, means guiding said side members along said tracks with the said platform projecting outwardly from said side members, means including a cable for supporting and moving said platform relative to said tracks, an elongate pressure plate xedly secured to and carried by each of said side members, said pressure plates disposed one each in parallel sliding relationship with a face of said tracks, an elongate brake `shoe for each of said pressure plates, a pair of vertically spaced parallel links pivotally interconnected between the mounting ears of each brake shoe and the adjacent side member whereby each brake shoe moves in parallelism with a corresponding pressure plate between lowered inoperative position spaced from a track and raised operative position in engagement with said track opposite the pressure plate, an actuatorrarm for each brake shoe, means pivotally securing said arms to said side members with the free outer ends of said arms beneath and in engagement with one ofthe mounting ears on each brake shoe, guide means `supported by said platform, a pulley cage meansslidably-mounted on said guide means, spring means normally urging said pulley cage means in a downward direction, the inner ends of said arms being pivotally connected with said pulley cage means, said cable being operatively connected with said pulley cage means such that the weight of the platform when lifted by the cable overcomes the counter force of said spring means for urging said pulley cage means upwardly with respect to the platform thereby causing the outer ends of the arms to move downwardly causing the brake shoes to move into operative position, each of said arms being mounted for pivotal movement about an axis Which is substantially normal to the pivotal axis of the associated links connected with the associated brake shoe.

References Cited in the tile of this patent UNITED STATES PATENTS 313,451 Rogers Mar. 3, V1885 324,493 See Aug. 18, 1885 497,433 Settle May 16, 1893 1,389,867 Griffin Sept. 6, 1921 o 2,407,655 vDiSanti Sept. 17, 1946 FOREIGN PATENTS 1,001 Great Britain Nov. 6, 1913 232,435 Great Britain Apr. 23, 1925 

